No

Diuretic, Loop

Management of edema associated with congestive heart failure and hepatic or renal disease; used alone or in combination with antihypertensives in treatment of hypertension; I.V. form is indicated when rapid onset is desired

B

Clinical effect on the fetus: A decrease in fetal weight, an increase in fetal resorption, and delayed fetal ossification has occurred in animal studies

Hypersensitivity to torsemide, any component, or any sulfonylureas; anuria

Adjust dose to avoid dehydration. In cirrhosis, avoid electrolyte and acid/base imbalances that might lead to hepatic encephalopathy. Ototoxicity is associated with rapid I.V. administration of other loop diuretics and has been seen with oral torsemide. Do not administer intravenously in less than 2 minutes; single doses should not exceed 200 mg. Hypersensitivity reactions can rarely occur. Monitor fluid status and renal function in an attempt to prevent oliguria, azotemia, and reversible increases in BUN and creatinine. Close medical supervision of aggressive diuresis is required. Monitor closely for electrolyte imbalances particularly hypokalemia and correct when necessary. Coadministration with antihypertensives may increase the risk of hypotension. Use caution in patients with known hypersensitivity to sulfonamides or thiazides (due to possible cross-sensitivity); avoid in patients with history of severe reactions.

1% to 10%:

Cardiovascular: Edema (1.1%), EKG abnormality (2%), chest pain (1.2%)

Central nervous system: Headache (7.3%), dizziness (3.2%), insomnia (1.2%), nervousness (1%)

Endocrine & metabolic: Hyperglycemia, hyperuricemia, hypokalemia

Gastrointestinal: Diarrhea (2%), constipation (1.8%), nausea (1.8%), dyspepsia (1.6%), sore throat (1.6%)

Genitourinary: Excessive urination (6.7%)

Neuromuscular & skeletal: Weakness (2%), arthralgia (1.8%), myalgia (1.6%)

Respiratory: Rhinitis (2.8%), cough increase (2%)

<1% (Limited to important or life-threatening symptoms): Syncope, atrial fibrillation, hypotension, ventricular tachycardia, shunt thrombosis, hypovolemia, GI hemorrhage, rash, rectal bleeding, angioedema

Symptoms include electrolyte depletion, volume depletion, hypotension, dehydration, circulatory collapse; electrolyte depletion may be manifested by weakness, dizziness, mental confusion, anorexia, lethargy, vomiting, and cramps

Following GI decontamination, treatment is supportive; hypotension responds to fluids and Trendelenburg position

CYP2C9 enzyme substrate

Aminoglycosides: Ototoxicity may be increased.

Anticoagulant activity is enhanced.

Antidiabetic agents: Glucose tolerance may be decreased.

Antihypertensive agents: Effects may be enhanced.

Beta-blockers: Plasma concentrations of beta-blockers may be increased with torsemide.

Chloral hydrate: Transient diaphoresis, hot flashes, hypertension may occur.

Cisplatin: Ototoxicity may be increased.

Digitalis: Arrhythmias may occur with diuretic-induced electrolyte disturbances.

Enzyme inducers (phenytoin, phenobarbital, carbamazepine) theoretically may reduce efficacy of torsemide.

Lithium: Plasma concentrations of lithium may be increased; monitor lithium levels.

NSAIDs: Torsemide efficacy may be decreased.

Probenecid: Torsemide action may be reduced.

Salicylates: Diuretic action may be impaired in patients with cirrhosis and ascites.

Thiazides: Synergistic effects may result.

If torsemide is to be administered via continuous infusion, stability has been demonstrated through 24 hours at room temperature in plastic containers for the following fluids and concentrations:

50 mg torsemide (10 mg/mL) added to 500 mL D₅W, 250 mL NS or 500 mL 0.45% sodium chloride

Inhibits reabsorption of sodium and chloride in the ascending loop of Henle and distal renal tubule, interfering with the chloride-binding cotransport system, thus causing increased excretion of water, sodium, chloride, magnesium, and calcium; does not alter GFR, renal plasma flow, or acid-base balance

Onset of diuresis: 30-60 minutes

Peak effect: 1-4 hours

Duration: ~6 hours

Absorption: Oral: Rapid

Protein binding: Plasma: ~97% to 99%

Metabolism: Hepatic by cytochrome P-450, 80%

Bioavailability: 80% to 90%

Half-life: 2-4; 7-8 hours in cirrhosis (dose modification appears unnecessary)

Elimination: 20% eliminated unchanged in urine; hemodialysis does not accelerate removal

Adults: Oral, I.V.:

Chronic renal failure: 20 mg once daily; increase as described above

Hepatic cirrhosis: 5-10 mg once daily with an aldosterone antagonist or a potassium-sparing diuretic; increase as described above

Hypertension: 5 mg once daily; increase to 10 mg after 4-6 weeks if an adequate hypotensive response is not apparent; if still not effective, an additional antihypertensive agent may be added

Renal function, electrolytes, and fluid status (weight and I & O), blood pressure

Torsemide may induce potent diuretic effects and, as with other potent diuretics, electrolytes and volume status needs to be closely monitored.

May cause dizziness

May cause agranulocytosis; use caution with clozapine and carbamazepine; may decrease lithium clearance resulting in an increase in serum lithium levels and potential lithium toxicity, however, this is much more common and significant with the thiazide diuretics; monitor serum lithium levels; concurrent use with chloral hydrate may produce hot flashes and hypertension

No information available to require special precautions

No effects or complications reported

Take recommended dosage with food or milk at the same time each day (preferably not in the evening to avoid sleep interruption). Do not miss doses, alter dosage, or discontinue without consulting prescriber. Include orange juice or bananas (or other potassium-rich foods) in daily diet; do not take potassium supplements without consulting prescriber. Do not use alcohol or OTC medications without consulting prescriber. You may experience postural hypotension; change position slowly when rising from sitting or lying. May cause transient drowsiness, blurred vision, or dizziness; avoid driving or engaging in tasks that require alertness until response to drug is known. You may have reduced tolerance to heat (avoid strenuous activity in hot weather or excessively hot showers). Increased exercise and increased dietary fiber, fruit, and fluids may reduce constipation. Report unusual weight gain or loss (>5 lb/week), swelling of ankles and hands, persistent fatigue, unresolved constipation or diarrhea, weakness, fatigue, dizziness, vomiting, cramps, change in hearing, or chest pain or palpitations. Breast-feeding precautions: Consult prescriber if breast-feeding.

Administer the I.V. dose slowly over 2 minutes

Monitor renal function, electrolytes, and fluid states closely including weight and I & O

Injection: 10 mg/mL (2 mL, 5 mL)

Tablet: 5 mg, 10 mg, 20 mg, 100 mg

Fowler SF and Murray KM, "Torsemide: A New Loop Diuretic," Am J Health Syst Pharm, 1995, 52(16):1771-80.

Friedel HA and Buckley MM, "Torsemide. A Review of Its Pharmacologic Properties and Therapeutic Potential," Drugs, 1991, 41(1):81-103.

Hariman RJ, Bremner S, Louie EK, et al, "Dose-Response Study of Intravenous Torsemide in Congestive Heart Failure," Am Heart J, 1994, 128(2):352-7.

Rudy DW, Gehr TW, Matzke GR, et al, "The Pharmacodynamics of Intravenous and Torsemide in Patients With Chronic Renal Insufficiency," Clin Pharmacol Ther, 1994, 56(1):39-47.

Vargo DL, Kramer WG, Black PK, et al, "Bioavailability, Pharmacokinetics, and Pharmacodynamics of Torsemide and Furosemide in Patients With Congestive Heart Failure," Clin Pharmacol Ther, 1995, 57(6):601-9.